<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>参数默认值</title>
</head>

<body>
  <script>
    // ES6 允许给函数参数赋值初始值
    // 1. 形参初始值 具有默认值的参数， 一般位置要靠后(潜规则)
    /* 
      function add(a, b, c=10) {
        return a + b + c;
      }
      let result = add(1, 2);
      console.log(result); 
    */

    // 2. 与解构赋值结合
    /* 
      function connect(options) {
        let host = options.host;
        let username = options.username;
      }

      connect({
        host: 'localhost',
        username: 'root',
        password: 'root',
        port: 3306
      }) 
    */

    function connect({host="127.0.0.1", username, password, port}) {
      console.log(host, username, password, port)
    }

    connect({
      host: 'atguigu.com',
      username: 'root',
      password: 'root',
      port: 3306
    })
  </script>
</body>

</html>